1. Field of the Invention
This invention relates to an optical connector device to be used in the field of optical communication between equipments in an OA (office automation) system, a FA (factory automation) system, an automobile and so on.
2. Background Art
One example of optical connector devices, currently used in an automobile, is shown in FIG. 14, and this connector device includes a socket-type optical connector 1 and a plug-type optical connector 2 which can be releasably connected together. The socket-type optical connector 1 includes a metal ferrule 4, mounted on an end portion of an optical fiber cord 3 to hold an end portion of an optical fiber, a socket-type housing 5, which receives the metal ferrule 4, and holds this metal ferrule 4 in a predetermined posture, a coil spring 6, which is mounted within the socket-type housing 5 to resiliently urge the metal ferrule 4 in a predetermined direction, a spring retainer 7, which is mounted at an end portion of the socket-type housing 5 to retain the coil spring 6 against withdrawal, and a boot 8 which is mounted on the end portion of the socket-type housing 5, and extends from this end portion to cover the optical fiber cord 3.
Generally similarly, the plug-type optical connector 2 mainly includes a metal ferrule 14, mounted on an end portion of another optical fiber cord 13 to hold an end portion of an optical fiber, a plug-type housing 15, which receives the metal ferrule 14, and holds this metal ferrule 14 in a predetermined posture, a coil spring 16, which is mounted within the plug-type housing 15 to resiliently urge the metal ferrule 14 in a predetermined direction, a spring retainer 17, which is mounted at an end portion of the plug-type housing 15 to retain the coil spring 16 against withdrawal, and a boot 18 which is mounted on the end portion of the plug-type housing 15, and extends from this end portion to cover the optical fiber cord 13.
The plug-type housing 15 of the plug-type optical connector 2 is formed into a narrow, elongate tubular shape, and a sleeve member 19 is received within this housing, and a front end portion of the metal ferrule 14 is fitted in this sleeve member, so that this sleeve member holds the metal ferrule 14 in the predetermined posture.
When the front end portion of the plug-type housing 15 is fitted into a fitting recess 5a in the socket-type housing 5, a retaining portion 15a, formed on an outer peripheral surface of the plug-type housing 5 at the front end portion thereof, is releasably and retainingly engaged with a retaining portion 5b formed on the socket-type housing 5, so that the two housings are connected together. At this time, the front end portion of the metal ferrule 4 is fitted into the other end portion of the sleeve member 19, so that the two optical fiber cords 3 and 13 are optically coupled together.
In this conventional optical connector device, the metal ferrules 4 and 14, as well as the housings 5 and 15, are independent, and these independent metal ferrule 4 and 14 are forcibly abutted against each other by the resilient forces of the coil springs 6 and 16, thereby providing the connector-connected condition which is less liable to be affected by the fitted condition of the retaining portions 5b and 15a formed respectively on the socket-type housing 5 and plug-type housing 15. However, the number of the component parts, including the metal ferrules 4 and 14, the coil springs 6 and 16 and the spring retainers 7 and 17, is large, and therefore there has been encountered a problem that the assembling operation requires much time and labor, and is cumbersome.
Therefore, there has been proposed the type of optical connector device in which a ferrule portion for holding an end portion of an optical fiber is formed integrally with each of a socket-type optical connector and a plug-type optical connector in order to reduce the number of the component parts and to reduce the time and labor for the assembling operation. In such an optical connector device, when a fitting projection portion of the plug-type optical connector is fitted into a fitting recess in the socket-type optical connector, a latch portion, provided at the plug-type optical connector, is releasably and retainingly engaged with a latch retaining portion, provided at the socket-type optical connector, and therefore the end surfaces of the two optical fibers are connected together in a butting manner, so that the two optical fiber cords are optically coupled together.
In this kind of optical connectors, there is used the system in which the end surfaces of the optical fibers are connected together in a butting manner, thereby securing a passage for light, and therefore a light loss, developing in the connected condition of the optical connectors, is much influenced by the butt-connected condition of the optical fiber end surfaces.
In the structure of connecting the socket-type and plug-type optical connectors each having the integral ferrule portion, the latch portion can be elastically deformed and moved to be releasably and retainingly engaged with the latch retaining portion, and therefore a relative shaking movement between the two optical connectors is liable to occur in the connected condition. There has been encountered a problem that the dimensional tolerances must be strictly controlled in order to stabilize and reduce the light loss in the connected condition.